Mutants of theαchain commonly are present to the extent of 20-25% of a heterozygote's hemoglobin. A major exception is Hb Fort Worth (α227(β8)Glu→Glyβ2) which was first identified in a Black family by Schneideret al.(1) and has now been reported by Carstairset al.(2) in a second Black family. In all heterozygotes, this variant accounts for only 4-5% of the total hemoglobin. As Carstairset al.note,“The reason for the low quantity of Hb Fort Worth in heterozygotes (4-5%) remains unclear.”Perhaps, in a manner analogous to Hb E, abnormal mRNA processing may be responsible.